Allow loading allure plugin on secondary TeamCity nodes

[Dead-off]

TeamCity CI supports multi-node installations. By default, the TeamCity cluster may have one main node and many secondary nodes. Secondary nodes require a special attribute in the plugin descriptor which allows loading the plugin on the secondary node. This is required since

• when a plugin has some state in the external system it may cause various issues if the plugin will work on both nodes in parallel.
• TeamCity secondary nodes have configured security manager which may block some network and file operations unless these operations were explicitly allowed.

See TeamCity documentation for details:
https://plugins.jetbrains.com/docs/teamcity/plugin-development-faq.html#How+to+adapt+plugin+for+secondary+node
https://www.jetbrains.com/help/teamcity/multinode-setup.html

At the same time, not loaded plugin causes various issues on the secondary node, for example:
https://youtrack.jetbrains.com/issue/TW-71538
https://youtrack.jetbrains.com/issue/TW-71544

I reviewed the code of the allure plugin and didn't find any problem related to work in a multi-node setup. Looks like one can safely enable this plugin on TeamCity secondary nodes.